kea/tools/extract_bnf.sh.in

#!/bin/sh

# Copyright (C) 2019 Internet Systems Consortium, Inc. ("ISC")
#
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

# Get BNF grammars from bison files
#
# This script takes 1 or 2 parameters:
#
# Basic usage:
# ./extract_bnf.sh <bison-file-base-name> - will generate BNF notation in plain text
#
# Markdown:
# ./extract_bnf.sh <bison-file-base-name> --markdown

# Check if there are one or two arguments
if [ $# -ne 1 ] && [ $# -ne 2 ]; then
    echo "extract_bnf.sh <bison-file-base-name> [--markdown]"
    exit 1
fi

markdown=0
if [ $# -eq 2 ] && [ "$2" = "--markdown" ]; then
    markdown=1
fi

# Get the output file
base=$1
output=

if [ -f "${base}.output" ]; then
    output="${base}.output"
elif [ -f "${base}.yy" ]; then
    /usr/bin/bison -v "${base}.yy" -o output
    rm -f output output.h *.hh
    mv output.output /tmp/output
    output=/tmp/output
else
    echo "cannot find ${base}.yy"
    exit 1
fi

# Process the output file
#  - extract the grammar part
#  - remove line numbers
#  - remove intermediate productions
#  - remove intermediate non-terminals
#  - replace standard tokens
#  - replace : by BNF ::=
#  - squeeze multiple blank lines

cat $output |\
@AWK@ '/^Terminal/ { exit }; // { print }' |\
@AWK@ '// { gsub("^ +[0-9]+ ", ""); print }' |\
@AWK@ '/^\$@[0-9]+:/ { next }; // { print }' |\
@AWK@ '// { gsub(" \\$@[0-9]+ ", " ") ; print }' |\
@AWK@ '// { gsub("\"constant string\"", "STRING"); print }' |\
@AWK@ '// { gsub("\"integer\"", "INTEGER"); print }' |\
@AWK@ '// { gsub("\"floating point\"", "FLOAT"); print }' |\
@AWK@ '// { gsub("\"boolean\"", "BOOLEAN"); print }' |\
@AWK@ '// { gsub("\"null\"", "NULL"); print }' |\
@AWK@ '// { gsub("\"constant hexstring\"", "HEXSTRING"); print }' |\
@AWK@ '// { gsub("\"option name\"", "OPTION_NAME"); print }' |\
@AWK@ '// { gsub("\"ip address\"", "IP_ADDRESS"); print }' |\
@AWK@ '// { gsub("\"end of file\"", "EOF"); print }' |\
@AWK@ '// { gsub("%empty", ""); print }' |\
@AWK@ '// { gsub(": ", " ::= "); print }' |\
cat -s > $output.2

if [ "$markdown" -eq 1 ]; then
    echo ".. code-block:: BNF" > $output.3
    echo "   :linenos:" >> $output.3
    cat $output.2 | @AWK@ '/^.+$/ { print "    ",$0 }; /^$/ { print } ' >> $output.3
    cat $output.3
else
    cat $output.2
fi